Molded polypropylene or other plastic appliance feet are well known in the art, for example, as described in U.S. Pat. No. 3,575,288 issued to B. L. Brucken. Typical feet are formed of a molded plastic piece, usually polypropylene, having a hollow shaft, threaded on the exterior and having an enlarged head which receives a resilient pad. The threaded shaft of the foot is screwed into a cooperating threaded portion of an appliance so that the head and a portion of the shaft space the appliance from a supporting floor. The resilient pad placed at the lower portion of the head spaces the head from the floor and provides a non-skid pad which prevents the normal vibrations and oscillations of the appliance from moving the appliance to an out-of-level position. After having been leveled, by threading the shaft into the base of the appliance, the appliance will remain level and operation of the appliance will not be impaired with use by movement to an out-of-level position.
Prior feet which have used resilient pads have not held the pads firmly engaged enough on the head. With age, the rubber pads shrink or become loose on the appliance foot so that they can be easily removed from the foot by shear. This is a disadvantage where an appliance having the foot is moved by scooting it over a high friction surface, such as a concrete floor. The shear is sufficient to distort the rubber pad and remove it from the cooperating socket in the plastic foot. As a result, the pads often become lost from one or more feet and the feet are no longer effective to level or stabilize the appliance from its vibrations.
Applicant has devised a novel appliance foot having a resilient pad which does not become loose on the foot with age and which is retained in a cooperating portion of the foot with sufficient force that it cannot be easily removed by shear stresses applied to the pad. This new foot has a recess which receives a cooperating portion of the resilient rubber pad. The foot is tightly crimped down over a portion of the resilient pad so that the pad is tightly retained in the cooperating recess of the appliance foot.
The foot is preferably formed by injection molding of a suitable plastic material, such as polypropylene. The recess for receiving the pad is molded into the face of the foot. The rubber pad is installed in the recess while the foot is in a semi-plastic condition, preferably while the foot is still warm from the molding process. A cooperating portion of the pad is forced into the recess of the semi-plastic foot with a die. The foot, still semi-plastic, is placed in a second die which crimps the edge of the recess tightly against the pad. On cooling, the plastic foot shrinks somewhat, holding the pad even more firmly in the recess.
While it is preferred that the pad be installed while the foot is still warm from the molding operation, the pad can be installed in a foot which has been rewarmed.
By obtaining a tight crimp, applicant is able to produce a foot having an attached rubber pad which is retained in the pad, even when subjected to shear forces. The foot is effective to level an appliance and hold it in place under vibration even when age had deteriorated the normal resilient properties of the rubber.